Game starts: star fish shows at the bottom , up/down/left/right arrow keys can control the star fish, try to avoid the moving fish, if touch them or the black walls, go back to starting location. if passed the fish and touch the end point, change another backdrop to show "You win" and stop the game. The three fish(you can make only one) keep moving horizontally, if on edge bounce back.
challenge, use a score or health to record how many times the star fish touched the fish. (counting down) Add some sound if you like.